RCBS Jr3 and mil surplus 7.62 x 51 (mg brass ?) is it G to G ?

[Follow Me]

Greetings to all,
Decided to start prep work on a whole bunch of mil surp 7.62 brass ( probably fired in machine gun of some sort). Will my RCBS Jr3 handle the resizing job? Would not want to destroy a decent press because of lack of asking an important question.
Thank you for your time in responding to my question.

Warm regards
Follow Me

[bustermchooter]

Yes


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[rcslotcar]

I use a jr 3 to do some swaging,,I don't see any problems.

[white cloud]

That is an excellent press. I regret the day I sold mine. It will be fine for what your are trying to do.

[red67]

I guess I'll be the lone dissenter. The RCBS JR presses are great old presses, but they are intended for pistol or small rifle cases. An RCBS rock chucker would be more suitable for your intended use.

The Jr presses don't have compound linkage and therefore have less leverage for full length resizing.

[David2011]

Using pure lanolin will help. It works better under high pressure than any lube I’ve tried. The alcohol and lanolin spray lube is good as is Imperial but they just don’t have the lubricity of straight lanolin.

[Three44s]

Clean the brass well and then sparingly use Imperial or Lyman Unique slightly more liberally.

You may need a small base sizer die. Size a few with the sizer die you have and then wipe them off and try in the firearm you intend to reuse them in.

If they chamber with some resistance I would weight the choice between a SB sizer die and getting different brass to fool with (resell your MG brass).

Three44s

[EDG]

The force required on the handle may be a bit high.
Size each case slowly and let the ram dwell at the top of the stroke for 3 to 5 seconds.
Then lower the ram about 1/2" and spin the case 1/2 turn and size again slowly with another dwell.
Check your cases to make sure they chamber before sizing a bunch.

[dverna]

I guess I'll be the lone dissenter. The RCBS JR presses are great old presses, but they are intended for pistol or small rifle cases. An RCBS rock chucker would be more suitable for your intended use.

The Jr presses don't have compound linkage and therefore have less leverage for full length resizing.

Agree... But give it a try. Just don't lean on it too much or you may damage a nice press.

I had a heck of a time resizing brass that had gone through a machine gun.

[country gent]

While it will probably do the job force required is going to be higher than normal even more so if you have to go to a small based die and or bump the shoulder back a lot. Wear and tear on the press will be heavier due to this. For heavy reforming or sizing I use a heavier press ( Lyman orange crusher or rockchucker). Several things when starting this project clean and lube the press before starting. This gives the machine the best operation conditions. Use a good sizing lube applied lightly but evenly to the cases. I will recommend Imperial sizing die wax also. Another is clean polished brass sizes easier then dirty.

[tward]

I’ve had good luck with Lee case lube thinned with alcohol nice light coat just leaves a haze. It seemed to work better than Imperial and was easier to clean off the cases. I was using it to turn 357 mags into 256 Winchester. Good luck, Tim

[mortyg]

I think I would do a little PM on the press. First, take the bottom pin out and clean lube then drop the ram clean the ram and the cylinder, lube well. Don't forget the upper pin.

MG brass is usually very dirty. I would de-prime and swage then clean in a caustic bath of hot water, dry. Scratch test the brass. Spray with dillion lube and let dry. I use imperial wax/lube. If you are going to use the brass in a gas gun I would first size with a standard die then a SB die. I would lube with Imperial push the handle till it gives strong resistance then lift, re-lube and turn the case and repeat till it is sized. It will take a bit of time and effort.

[1hole]

The "old" C frame presses were made plenty strong enough to do any common reloading tasks. I used one for the first 25 years of my reloading career and it did everything for me, including case forming military .30-06 to .22-250, without breaking a sweat. FL sizing your .308 machine gun cases will never match the effort of doing that!

Your press lacks "compound" leverage so it will take more effort than otherwise but using it won't be so hard that you'll develop gorilla biceps. What you WILL need (with any simple toggle link press) is a very sturdy bench to reduce the wasted effort just to flex the bench when completely FL sizing your cases. I like to have a leg directly under the press, a single 2x4 is plenty strong enough.

Apply a good case sizing lube, especially on the lower body (near the head). Then you shouldn't see much difference in effort even if the cases did come from a machine gun range. BUT - IF it seems very hard to fully insert a case into your FL die, stop!, lower the ram, take the case out and reapply lube ONLY on the lower case before you try it again. If you try to ram a case all the way home on first try no matter how strongly it signals you not to, you will soon be buying a stuck case remover!

Have fun!

[wmitty]

I have had a tough time with 7.62 mg fired brass. I was using rockchucker and imperial and it was difficult. Must’ve been very large chamber or something. I wound up using STP as lube (nasty). Went to Redding ultra mag and much improvement.

[samari46]

Rough tumble the brass to get the bulk of the crud off it. Bore brush inside the case neck to clean it up and Imperial die sizing wax with a little on the case mouth. That's how I do it. The junk inside the case mouth contributes a lot to the force you need to get the expanding button into the case necks Deprime and clean primer pockets prior to tumbling. Also keeps your media cleaner longer. Frank

[fn1889m]

I went from an RCBS Jr to a RC Supreme because of the effort it took to resize MG brass. In retrospect that was the only task for which I needed a larger press. It did make a difference.

[Willbird]

The biggest thing with any press is how it is mounted to the bench. Growing up my dad had a less than stellar reloading bench, it was large and had drawers for storage but it was not really rigid. Full length resizing rifle brass such as 30-06 and 7.62 NATO was a dramatic affair that involved nails rising up out of the bench top every session .

We were using an RCBS JR press.

Fast forward about 20 years, dad has passed and I bolt the same press down to the table of my Bridgeport milling machine using toe clamps, wow it is now a totally different press with super powers compared to being mounted on a fairly flimsy bench.

Good rigid press mounting allows you to size the case without having to get a lunging running start at the process .

Bill

[astroturf3040]

Greetings to all,
Decided to start prep work on a whole bunch of mil surp 7.62 brass ( probably fired in machine gun of some sort). Will my RCBS Jr3 handle the resizing job? Would not want to destroy a decent press because of lack of asking an important question.
Thank you for your time in responding to my question.

Warm regards
Follow Me

I used a Jr for same job. Clean brass, pm press, and all other hacks above apply. I punched primers first. I FL sized without expander ball. I then fl sized with expander ball, half in, retract, turn, size. Reamed primer crimp. Trimmed cases to length. Beveled case mouth. Redding lube on some. Lee lube worked. Did a 1000. Lesson learned. Years ago. No more mg brass! Great press, keep clean and lubricated. RC would have been less work I think. Thanks

[lightman]

I guess I'll be the lone dissenter. The RCBS JR presses are great old presses, but they are intended for pistol or small rifle cases. An RCBS rock chucker would be more suitable for your intended use.

The Jr presses don't have compound linkage and therefore have less leverage for full length resizing.

I agree. The JR press should handle this ok but an "O" frame press with compound linkage like the Rcckchucker will do the job easier.

I've used lots of machinegun brass, both M2 and 7.62. Using a small base die for the first sizing really helps, as does a good lube. The old fashion STP type stuff works well for this, about the only time I use it anymore. Also, lubing the inside of the case neck will reduce the required effort a little, and every little bit helps! I once had some stuff fired in a 1919 that almost needed a cheater pipe on the Rockchucker handle! Man it was hard to size.

[frkelly74]

I would say it will work. Lubing the case will be key to getting it to work. Be sure to lube the inside of the necks also to prevent stretching the cases when you take them out of the die. I have found Castor Oil to be good lube although it will kill or weaken primers if it is allowed to stay in the case. Hopefully it is a one time deal and you don't have to abuse your press very much. If it will be ongoing then get a bigger , heavier press or even a Lyman or other sizing die that you use with an arbor press or bench vice. That is what I resorted to way back when I had some old military 06 brass that would not fit my rifle. The vice put an interesting waffle pattern on the heads of those cases processed that way.